Copilot CLI incorrectly infers repository owner, ignoring git remote configuration

### Describe the bug

Copilot CLI incorrectly infers the repository owner/organization, even when the git remote is correctly configured.

In my case, the remote is set to a private GitHub Enterprise (GHE/EMU) organization, but Copilot CLI infers a different owner instead.

### Affected version



### Steps to reproduce

1. Clone a repository from a private GHE/EMU organization (e.g., `git clone git@github.com:MyEnterpriseOrg/my-repo.git`)
2. Verify the remote is correct: `git remote get-url origin` shows the correct enterprise org
3. Run a Copilot CLI command that references the repository, e.g.:
copilot -p "Show me this week's commits and summarize them" --allow-tool 'shell(git)'
4. Observe that Copilot infers a different/wrong owner

### Expected behavior

Copilot CLI should parse the git remote URL and correctly identify the owner from the configured remote.

### Actual behavior

Copilot CLI infers a different owner, possibly due to:
- Hardcoded defaults or legacy config
- Incorrect parsing of the remote URL or directory structure
- Internal cache or mapping that doesn't update when changing directories/remotes
- Issue specific to GHE/EMU organization handling

### Related issues

- #1167 - Similar issue where session selection uses branch name only, not full repository identity

### Additional context

- Repository is in a **private GitHub Enterprise (EMU) organization**
- This may be related to session caching or how the CLI resolves enterprise vs non-enterprise orgs